Implantable Cardioverter‐Defibrillator Therapy in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy: Predictors of Appropriate Therapy, Outcomes, and Complications

BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy is characterized by ventricular arrhythmias and sudden cardiac death. Once the diagnosis is established, risk stratification to determine whether implantable cardioverter‐defibrillator (ICD) placement is warranted is critical. METHODS AND RESULTS: The cohort included 312 patients (163 men, age at presentation 33.6±13.9 years) with definite arrhythmogenic right ventricular dysplasia/cardiomyopathy who received an ICD. Over 8.8±7.33 years, 186 participants (60%) had appropriate ICD therapy and 58 (19%) had an intervention for ventricular fibrillation/flutter. Ventricular tachycardia at presentation (hazard ratio [HR]: 1.86; 95% confidence interval [CI], 1.38–2.49; P<0.001), inducibility on electrophysiology study (HR: 3.14; 95% CI, 1.95–5.05; P<0.001), male sex (HR: 1.62; 95% CI, 1.20–2.19; P=0.001), inverted T waves in ≥3 precordial leads (HR: 1.66; 95% CI, 1.09–2.52; P=0.018), and premature ventricular contraction count ≥1000/24 hours (HR: 2.30; 95% CI, 1.32–4.00; P=0.003) were predictors of any appropriate ICD therapy. Inducibility at electrophysiology study (HR: 2.28; 95% CI, 1.10–4.70; P=0.025) remained as the only predictor after multivariable analysis. The predictors for ventricular fibrillation/flutter were premature ventricular contraction ≥1000/24 hours (HR: 4.39; 95% CI, 1.32–14.61; P=0.016), syncope (HR: 1.85; 95% CI, 1.10–3.11; P=0.021), aged ≤30 years at presentation (HR: 1.76; 95% CI, 1.04–3.00; P<0.036), and male sex (HR: 1.73; 95% CI, 1.01–2.97; P=0.046). Younger age at presentation (HR: 3.14; 95% CI, 1.32–7.48; P=0.010) and high premature ventricular contraction burden (HR: 4.43; 95% CI, 1.35–14.57; P<0.014) remained as independent predictors of ventricular fibrillation/flutter. Complications occurred in 66 participants (21%), and 64 (21%) had inappropriate ICD interventions. Overall mortality was low at 2%, and 4% underwent heart transplantation. CONCLUSION: These findings represent an important step in identifying predictors of ICD therapy for potentially fatal ventricular fibrillation/flutter and should be considered when developing a risk stratification model for arrhythmogenic right ventricular dysplasia/cardiomyopathy.